Snapshot
Crystal Sunset, Riksgränsen, Sweden 20 February 2014 Etienne Rebuffet
This beautiful image of the sunset over the Bjørnfjell mountain near Riksgränsen in northern Sweden shows two distinct optical phenomena. The picture contains a combination of crepuscular rays and a halo around the sun. Crepuscular rays are caused by rays of sunlight passing between gaps in relatively opaque objects such as clouds or hills. The objects cast shadows next to the lighter rays causing the parallel “pillars of light” effect in the image radiating away from the sun. The halo is caused
Bulletin of the Australian Meteorological and Oceanographic Society Vol. 27 page 35
by the refraction of light through hexagonal ice prisms suspended in the atmosphere. The halo was seen over the mountain for most of the day (in fact the sun never rose above the hill), and the ground-level temperature was a chilly -10°C. If you have an image of the weather near you to share, send it to duncan.ackerley@monash.edu, or post it on the AMOS Facebook page. — Ed